Protective relays can be found in any environment that uses electricity, from factories to power utilities. Relaying protection applications may include motors, generators, transformers, station-buses, lines and circuits, system grounds, network systems, pilot wires, pilot channels, transmission lines, pilot relaying, backup, reclosing, synchronizing, load-shedding, frequency and many more.
Typically, relays operate in combination with current and potential transformers, which reduce the high current and potential inputs to levels usable by relays, meters and/or other instruments associate therewith. Relays are electrically connected to an electrical system through a test switch terminal. In this manner, each test switch can be associated with one or more relays. It is typically necessary to short circuit the line and load terminals during relay removal or when an adjacent test switch is opened. The test switch provides this necessary short circuit or bypass feature.
Though current test switches are reliable and robust, changing customer usage and new unpredictable uses demand greater flexibility in test switch design. Accordingly, there is a need in the art for a more flexible test switch capable of addressing expanded customer needs.